[Blink] Modify SuspendableScriptExecutor to take a v8::Function

extensions/renderer/script_context.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "extensions/renderer/script_context.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/strings/string_split.h"
@@ skipping 184 matching lines @@
   }
 
   v8::Local<v8::Object> global = v8_context()->Global();
   if (!web_frame_)
     return handle_scope.Escape(function->Call(global, argc, argv));
   return handle_scope.Escape(
       v8::Local<v8::Value>(web_frame_->callFunctionEvenIfScriptDisabled(
           function, global, argc, argv)));
 }
 
+void ScriptContext::SafeCallFunction(const v8::Local<v8::Function>& function,
+                                     int argc,
+                                     v8::Local<v8::Value> argv[]) {
+  v8::HandleScope handle_scope(isolate());
+  v8::Context::Scope scope(v8_context());
+  v8::MicrotasksScope microtasks(isolate(),
+                                 v8::MicrotasksScope::kDoNotRunMicrotasks);
+  v8::Local<v8::Object> global = v8_context()->Global();
+  if (web_frame_) {
+    web_frame_->requestExecuteV8Function(function, global, argc, argv, nullptr);
+  } else {
+    // TODO(devlin): This probably isn't safe.

[dcheng, 2016/10/04 05:58:49]

Hmm, is it possible to attach devtools to a service worker? I'm just trying to
think of the normal ways we would get script re-entrancy. If devtools is
attached, how do we suspend script execution in the SW?

[Devlin, 2016/10/04 19:40:05]

That sounds like a question for falken. :)  Regardless, we'd definitely need
something different, since SWs don't have associated frames.

[falken, 2016/10/05 00:19:55]

Yes, you can attach DevTools to service workers and set breakpoints etc.
+dgozman.

[dgozman, 2016/10/05 01:25:42]

This should be fine as long as you execute JS via SuspendableScriptExecutor,
which is an ActiveDOMObject. We pause all of these while on breakpoint.

+    function->Call(global, argc, argv);
+  }
+}
+
 v8::Local<v8::Value> ScriptContext::CallFunction(
     const v8::Local<v8::Function>& function) const {
   DCHECK(thread_checker_.CalledOnValidThread());
   return CallFunction(function, 0, nullptr);
 }
 
 Feature::Availability ScriptContext::GetAvailability(
     const std::string& api_name) {
   DCHECK(thread_checker_.CalledOnValidThread());
   if (base::StartsWith(api_name, "test", base::CompareCase::SENSITIVE)) {
@@ skipping 286 matching lines @@
     v8::Local<v8::Value> argv[]) {
   return context_->CallFunction(function, argc, argv);
 }
 
 gin::ContextHolder* ScriptContext::Runner::GetContextHolder() {
   v8::HandleScope handle_scope(context_->isolate());
   return gin::PerContextData::From(context_->v8_context())->context_holder();
 }
 
 }  // namespace extensions